On the go and no time to finish that story right now? Your News is the place for you to save content to read later from any device. Register with us and content you save will appear here so you can access them to read later.

The West Coast Regional Council said the new variation would add 46.4ha of disturbance to the area granted in the initial consents, though it did not have figures for the pit area.

The Reefton mine had been subject to numerous variations in the past 11 years, including land swaps, regional council consents and compliance manager Colin Dall said.

Green Party MP and conservation spokeswoman Eugenie Sage said the mine area had been increased by stealth. It was "really bad practice" under the Resource Management Act to grant consents for "more and more" development. She said the increase should have been publicly notified.

Oceana Gold Reefton mine general manager Nigel Slonker said the 55ha was a mix of mature and regenerating beech forest and scrub.

"The overall mine area is unchanged and has not changed since access was granted in 2001. Within the mine boundary, areas are progressively disturbed and then rehabilitated over time, in accordance with a comprehensive restoration plan."

West Coast Conservation Board chairwoman Clare Backes said the board felt the loss could not be compensated for.

The board unsuccessfully asked DoC not to grant the concession variation.

She said that because a wildlife corridor would disappear - a continuous set of reserves and conservation land that allows wildlife to move from the coast to the Southern Alps - it would have more widespread effects than just localised destruction of flora and fauna.